PCSK9 Modulates Macrophage Polarization-Mediated Ventricular Remodeling after Myocardial Infarction

Area of Science:

• Cardiovascular Research
• Immunology
• Molecular Medicine

Background:

• High-risk patients with coronary heart disease, including acute myocardial infarction (AMI), increasingly use PCSK9 inhibitors.
• The role of PCSK9 in myocardial repair and its modulation of immune inflammation post-AMI remain unclear.
• Understanding PCSK9's function in cardiac repair is crucial for optimizing treatment strategies.

Purpose of the Study:

• To investigate the role of PCSK9 in macrophage immunomodulation following AMI.
• To elucidate the molecular mechanisms by which PCSK9 influences cardiac repair after myocardial infarction.
• To provide evidence supporting the clinical use of PCSK9 inhibitors in improving cardiac repair post-AMI.

Main Methods:

• Established an AMI model in wild-type and PCSK9 knockout mice.
• Assessed cardiac function, infarct size, and inflammatory cell infiltration.
• Investigated PCSK9's effect on macrophage polarization in vivo and in vitro, including macrophage depletion studies and analysis of the TLR4/MyD88/NF-κB pathway.

Main Results:

• Higher PCSK9 expression correlated with worse cardiac function post-AMI.
• PCSK9 knockout reduced infarct size, improved cardiac function, and decreased inflammatory cell infiltration.
• PCSK9 inhibition's therapeutic effects were dependent on macrophages and involved regulation of macrophage polarization via the TLR4/MyD88/NF-κB axis.

Conclusions:

• PCSK9 plays a significant role in modulating macrophage polarization after myocardial infarction.
• Macrophage polarization mediated by PCSK9 contributes to ventricular remodeling post-AMI.
• Targeting PCSK9 may represent a novel therapeutic strategy to enhance cardiac repair following myocardial infarction.